Research efforts to develop topical microbicides for intravaginal use for the prevention of sexually transmitted infections (STI) including HIV have been ongoing for over a decade. In the past year an estimated 4.3 million people became newly infected with HIV. Women now represent almost half of all adults living with HIV/AIDS. The need for a female controlled STI preventive product is well understood. Preclinical safety and efficacy testing of topical microbicide products must be performed prior to human use to assess the product's effects on the vaginal ecosystem and to assess potential anti-HIV activity. We have developed a useful model to evaluate the safety of topical microbicide products after vaginal use in the pigtailed macaque. We have used this model to study the effects of single and repeated applications of microbicides on vaginal microflora and epithelium. We have conducted preclinical safety and pharmacokinetic studies of vaginal gel formulations containing UC781 ( 1% and 0.1%) and tenofovir (1%) in this macaque model. In addition, we have the ability to image (MRI) product dispersal and transport in the female reproductive tract. In this proposed cooperative agreement, a novel delivery system for topical microbicides, vaginal films, will be compared to vaginal gel formulations. We will use our macaque model to assess safety, dispersal and pharmacokinetic characteristics of various film formulations containing UC781 and/or tenofovir, and compare these findings to those compiled for gel formulations. Finally, we will assess the efficacy of each of the developed film products using a macaque model for RT-SHIV infection. These studies will in part guide the optimization of a combination topical microbicide delivery system.